Onionsoidler: Here is where I have defined the variable...
CvImprovementInfo::CvImprovementInfo() :
...
m_iHappiness(0),
m_iPillageGold(0),
m_iImprovementPillage(NO_IMPROVEMENT),
m_iImprovementUpgrade(NO_IMPROVEMENT),
m_bActsAsCity(true),
m_bSeaBridge(true),
m_bHillsMakesValid(false)...